After Harriet refused Mr. Martin’s offer she was so “concerned at the idea of making him unhappy… and was so anxious that they should not fancy her ungrateful” Emma thought “if the young man had come in her way at that moment, he would have been accepted after all” (7). Emma “judged it best in every respect, safest and kindest, to keep her with them as much as possible” (8) at Hartfield. It was safest because Emma could reinforce the validity of her choice and so prevent any relapse on Harriet’s part and the kindest because Harriet was feeling so very low.

I am not sure Emma was worried illness and Mrs. Goddard’s nursing would induce Harriet to confess refusing Robert Martin. Of course it may be but to me the calendar does not seem agreeable. It is within the first two weeks of December that Mr. Martin proposes, is rejected and Harriet spends that night at Hartfield and the next begins a visit of several days. It is not until the 23rd of December that Harriet catches a cold. I think her day-spanning visit to Hartfield has ended and she has been sleeping in her own bed at the school because on the 23rd Harriet is only visiting that evening:

"The evening before this great event (for it was a very great event that Mr. Woodhouse should dine out, on the 24th of December) had been spent by Harriet at Hartfield, and she had gone home so much indisposed with a cold, that, but for [her] own earnest wish of being nursed by Mrs. Goddard, Emma could not have allowed her to leave the house." (13)

I thought Emma “could not have allowed her to leave the house” because she was “so much indisposed with a cold” (13); essentially Emma was being solicitous of Harriet’s health by not wishing her to travel even a small way in the cold. Also by this time Harriet has seen and absorbed Mr. Elton’s charade and treasured-up Emma’s hints and is feeling a great deal on his account and much less on Mr. Martin’s if her devaluing his letter (9) means anything. I think it is unlikely Emma was still worried Harriet would confide in Mrs. Goddard or anyone else about Mr. Martin’s proposal. Maybe I am wrong but it is nice to say something good of Emma. (:D)